


The Butteryfly Effect

by CaptainLaserBeam



Category: The Avengers (2012)
Genre: Angst, Bruce Feels, Hurt/Comfort, Insanity, M/M, Minor Character Death, Science Bros, Time Travel, Unresolved Sexual Tension
Language: English
Status: Completed
Published: 2012-10-24
Updated: 2012-10-24
Packaged: 2017-11-16 22:46:57
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 9,597
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/544679
Author URL: https://archiveofourown.org/users/CaptainLaserBeam/pseuds/CaptainLaserBeam
Summary: <blockquote class="userstuff">
              <p>In chaos theory, the butterfly effect is the sensitive dependence on initial conditions, where a small change at one place in a deterministic nonlinear system can result in large differences to a later state.</p>
<p>It is a common trope when presenting scenarios involving time travel and with hypotheses where one storyline diverges at the moment of a seemingly minor event resulting in two significantly different outcomes.</p>
<p>Bruce has two choices.</p>
            </blockquote>





	The Butteryfly Effect

**Author's Note:**

> I don't even know what this is, but I had a dream that was something very similar to it, and my muse wouldn't let me sleep again until it was finished. so much else to do, but this got kicked first in line. gawd. my muse is cruel.
> 
> also, the minor character death is hard to explain since it borders on major. (not giving it away!) if anyone thinks i should change the tags, let me know, i just didn't want to scare anyone away due to non-permanence.

It was a cold day in December the first time Bruce saw him. He's not entirely sure when it was precisely, or what day of the week, but at the time, it didn't really matter.

He'd been working late, as usual, deep into the depths of one of the largest R&D labs of Stark Tower. Bruce couldn't recall the last time he'd been freely offered something so valuable, and although it was a rocky start in accepting such permission, he couldn't altogether say it was the wrong one. The kind of equipment at his disposal was either something he'd once wished for, or tried futilely to makeshift at some point in his exile. 

Everything else Stark had created or patented himself. And it showed.

Bruce had once worked side by side with some of the brightest minds in his field. He'd counted himself highest amongst them, reminded of his own arrogance at the time to be his eventual downfall. But never had Bruce met someone with the ingenuity and sheer brilliance of Tony Stark.

He'd like to say that that was the only reason that he'd stayed. Why, even after four months Bruce had yet to even find himself a bus schedule out of the city, let alone consider leaving permanently. He kept telling himself 'not yet, but soon', and for some reason, 'soon' still hadn't circled back around. The opportunities he'd been presented with, the equipment and resources at his disposal, and the chance of finding himself a cure was so much more possible now. Still, it wasn't why he hadn't left.

Tony was a hurricane. A force that could neither be predicted nor quelled. He was agonizingly stubborn, egotistic with the brains to back it up, and had more abandonment issues than Bruce himself possessed. Tony Stark was irritating, with no sense of self preservation, and he was the most incredible human being Bruce had ever met in his life.

Everyone knew who he was. The public face of weaponry and warfare for decades as a mantle he inherited from his father and had never made an ounce of effort to hide. The playboy billionaire. The genius prodigy. Iron Man. The icon of wealth, indulgence and pride.

But that wasn't really him at all. At least, not that Bruce had seen. Tony was opinionated, sure, what genius wasn't? Beneath the tabloids and the rumors that followed close on the heels of all celebrity, was a damaged, needy human being at the mercy of his past mistakes. Something Bruce could certainly relate to. 

They'd bonded by chance at their first meeting, and ever since Bruce had found himself at something of a loss at what to do with that information. Were they friends? Did he dare to even have friends? It had been so long, did Bruce even know what that meant? And even if he did have a problem with it, Tony would probably just weasel his way back under his skin like he belonged there. Social labels or not.

Bruce caught himself smiling into the silent lab that night, but quickly shook it away. He was working, he didn't have the time for sentimentality and couldn't afford any mistakes. The beast dwelling beneath Bruce's skin, at all times, didn't take too fondly to unexpected surprises, and a chemical explosion was certainly that.

A thought that came quickly to the forefront of his thinking when the lights suddenly flickered around him.

Bruce froze, eyes moving to the ceiling as he contemplated exactly what it would take for electrical issues to arise within the tower. It was run essentially by itself with the renewable energy of the arc reactor, without relying on a city grid or public maintenance. The only thing that would turn the large power source off would be manual or physical force.

“JARVIS? Is there something wrong that I should know about?” Bruce asked the room, already long since used to the artificial intelligence that Tony relied on for most of his life. It had unnerved him a little at first, knowing that eyes would always be on him, but Bruce had come to depend on JARVIS almost as much as Tony did.

What unnerved him now, however, was the lack of response at all.

“JARVIS?” Bruce asked again, moving to stand to his feet before the lights suddenly died altogether. Bruce crouched down instantly, years of experience as a target teaching him that moving around when he couldn't see but someone else probably could was not a good plan. 

There was a flash of light from the corner, a few sparks that sounded like there was short circuiting machinery followed by a sudden blast of air, and then nothing. Silence.

Bruce swallowed hard, trying to adjust his vision before the lights suddenly blinked back on. Like nothing had happened. He blinked hard trying to adjust, still not standing, but taking in the room as a whole to see what might have changed.

Standing in the far corner of the room, arms crossed over his chest and leaning forward like he was in some kind of pain, stood a man. Completely naked, his head bent forward and face hidden from view.

Bruce startled, standing to his feet and taking a step forward with widened eyes. The thought of danger was not far from his thoughts, and the beast stirred, but Bruce tamped it down. Where had he come from?

“Hey!” He called out. “Are you-”

The lights flickered again. And then the figure was gone.

Bruce's breath caught in his throat. He blinked. Then again, mouth moving wordlessly with a hundred questions that he couldn't bring to sound.

_'Do you require assistance, Dr. Banner?'_

Bruce nearly jumped out of his skin, but maintained his control, placing a hand on the desk beside him as he stared vacantly towards the now empty spot. He stood in silence at the innocent question for a few heartbeats before swallowing hard.

“No, JARVIS, thanks, I uh- have I been the only one here? Is there anyone else in the lab right now?” He felt ridiculous asking, but couldn't stop himself. If he couldn’t trust his own eyes…

_'There have been no authorized or unauthorized entrances or exits, Doctor. Were you expecting someone?'_

Bruce shook his head, finally letting himself take a breath. He was overtired, probably underfed, and seeing things that weren't there. Not the time to be doing meticulous calculations then. He huffed a small laugh.

“Not expecting anyone, thanks JARVIS. Would you mind please saving the work I've done and powering it down?”

Bruce shook it off as a fluke, and purged it from his memory.

Until a month later.

It was January, and there was snow everywhere, blanketing the streets of New York nearly fifty stories down below where Bruce currently sat. He was carefully taking notes, staring into a microscope at a small drop of his own blood. Any more than that would have been hazardous if exposed, so he kept a tight lid on it at all times.

“Hey! Why aren't you using that thing I got you?”

Bruce startled, his neat handwriting ending in a streak of ink to the edge of the paper. He shook his head and glanced over his glances at a smirking Tony, who looked fairly unapologetic in his interruption.

“Which thing would that be? You can't seem to stop giving me things.” He commented dryly, knowing he could joke about something so generous without feeling like he was insulting the man.

“You know, the _thing_. The one that Pepper wrapped for you for Christmas?” Tony hopped up to sit on the edge of the desk, feet dangling like a six year old as he chewed idly on a candy cane.

Bruce rolled his eyes. “Do you even know what you gave me for Christmas? Or are you just waiting for me to say it aloud for you?”

“Okay, so maybe shopping isn't my thing. I can't even remember the last time I did a holiday anything, thanks so much Mister Nostalgia America with his stupid tinsel tree. What did she find for you anyway?”

Bruce shrugged. “A few large sweaters, some really nice pens. The imported tea I really like. It was all thoughtful stuff.”

Tony grimaced. “And she signed that from me, too? Sweaters. What am I, your grandma? Not a damn piece of tech in the lot of it. When's your birthday, anyway?”

“Not interested in owning any tech, Tony, but thanks. It's not really all that easy to carry on me anyway.” Bruce said idly as he glanced back into his microscope. He scribbled down the rest of his incomplete sentence before he realized that Tony had gone quiet. It wasn't all that rare of an occurrence, but it gave him pause enough to look back at him.

Tony was fiddling with another candy cane and not looking at him. Bruce's eyes narrowed for a second before he realized what it was he'd said. “I'm not- I didn't mean-” He tried, but Tony waved him off.

“Wouldn't bug me if you did, Big Guy. You can't live with the symbol of American freedom himself and not be thinking about it, y'know? Just give me a heads up of your plans and I can hook you up with-”

“Honestly, Tony, I'm not going anywhere right now.” Bruce slowly took his glasses off, giving his friend a small, honest smile. “I just...I have everything I need right now. More than I need, actually. You've made sure of that already.”

Tony's face was unreadable for a moment as he pulled the candy cane from his mouth to look at the fine point that he'd sucked it down to. Bruce tried not to lick his lips.

“I know.” He finally shrugged like it was no big deal, before hopping off of the table with the sugar back in his mouth. “Just thought I’d remind you. I don't do the whole 'forced captivity' thing, even with people I'd like to keep my hands on.”

Bruce felt the heat on his neck at the comment but ignored it, choosing instead to raise up the expensive pen he’d been holding. “To answer your first question, by the way? I _am_ using the thing you got me.”

Tony smirked, walking around behind Bruce and dropping an unopened candy cane into his front shirt pocket with a single pat to his chest and a squeeze of his shoulders. It was a warmth that lingered.

“Here, some sugar on me. Or technically, on Thor. He's been hanging them everywhere so Clint and I are starting an intervention.”

“Oh? And that's to what, eat them all?”

Tony shrugged, already spinning on his heel and heading towards the doors. “I didn't claim brilliance for this particular endeavor, but it's working so far. Lemme know if Jolly Green wants any, that might actually put a dent in Thor's supply.” He glanced back once more and winked before slipping out the doors and letting them close. The room descended into silence.

Bruce couldn't help it, he smiled. Whatever Tony had come down for, he'd never mentioned it.

The lights flickered.

Bruce blinked, clearing his vision for a second just to make sure it wasn't him. “JARVIS? Is something going on?”

There was no answer, just like before. It was happening again. Bruce swallowed before pushing himself off of his chair to get to the floor. He hadn't been hurt a month ago, hadn't even thought it was real, but Bruce wasn't the taking chances type.

“JARVIS!” Bruce called out before the lights were just gone, and there was still no response. A flash of light from the corner and a strong wind suddenly blowing past him like a window had broken. Then nothing.

Mere moments later and the lights were back, revealing the same figure standing alone in the corner of the room. Appearing there like he'd been the whole time. He was doubled over again, and Bruce could see the man's shoulders heaving like he was fighting just to breathe.

Bruce debated internally, warring with himself whether or not to say anything, but it seemed like whatever hallucination he'd thought this was before was sticking around a little longer this time.

There was a gasp of air that sounded like someone breaching the top of a lake before the naked man suddenly fell to his knees. He let out a pained cry and Bruce couldn't ignore it any longer. He stood to his feet.

“Hey...um, are you...”

The lights flashed suddenly and Bruce froze, his eyes locked on where the man was kneeling, but losing sight of him with the darkening of his vision. By the time it stopped, and the lights came back on again, the figure was gone.

Bruce's hands were shaking, his shoulders tensed and skin tight. One time was a coincidence, but twice? And longer this time. Movement, sound.

“JARVIS?”

_'At your service, Doctor. How can I help?'_

Bruce floundered, unsure what to ask. Was he losing his mind? Did anyone else see what he had? Any cameras recorded it? Had an injured man really been there in the corner of the room or was he a ghost in Bruce's head? He ran his hands through his hair nervously and fought to calm his heart.

“N-Nothing, JARVIS, thank you, I, uh- nothing.”

Bruce didn't sleep again for three days.

A month later, it was the end of February, and Bruce had seen the man twenty three times.

The Avengers had been on missions together. They'd fought and bled and united with each other as well as a team of argumentative and stubborn personalities could. Bruce wasn't a fan of using the Other Guy when there was no real way he could control the beast's actions, but so far he'd been lucky. He followed orders and he listened to his teammates, as long as there was something for him to smash.

What Bruce still feared, however, was when he didn't. Who'd be the targets then? Who would take the beast's anger once he could no longer be controlled? This was a problem that weighed heavily over him, despite the protests of his team.

And then there was Bruce’s own, personal problems as himself.

The unexplained events had taken place at random points in time, generally after midnight and somehow in completely different labs. None had been recorded or noted by the in-house computer system and seemed to exist outside of time completely. Some lasted up to ten seconds, others less than one, but they were increasing in frequency as time went on. 

All signs pointed to an event that was leading toward destabilization. Not of Bruce's surroundings, but of Bruce himself.

“If I didn't know any better, I'd say your obsession with isolating yourself was due to a scientific breakthrough of some kind. If so, I demand to hear of it before the world does. I consider that fair penance for funding your research.”

Tony found him, as he usually did, holed up in yet another of the laboratory spaces that made up Stark Tower. Bruce knew better than to think Tony was being serious after long since realizing how much that the genius noticed more than others did.

“I'm not isolating myself.” Bruce grumbled, probably looking more like a cave troll as each day passed. Sleeping had never been easy to begin with, and this new _thing_ was just making it worse.

Tony snorted. “You're talking to the master here, Bruce. King of my castle, Master of my space. If I don't wanna be found, then I'm not. Unfortunately for you, I still own all the keys.”

That should have annoyed Bruce, but it really didn't. He liked that Tony could see him anytime he wanted. Liked when he showed up randomly to poke at him, talk shop, or sometimes even force him to go outside. Bruce's best days were when they could spend an entire day together building things from the ground up, just because they could.

It didn't even matter if Tony didn't feel the same way. Bruce had long since grown accustomed to admiring things silently and from a distance.

He sighed and rubbed a hand down his face, wishing he could scream out his frustrations like a normal person without turning into a rage monster. Unhealthy emotional management didn't even begin to cover it.

“Was there something you needed?” Bruce asked, a little more chipped than he usually was, which wasn't going to help Tony's suspicions at all. The man cocked an eyebrow at him, crossing his arms over his chest and leaning against the desk.

“No. Everything I need is either here, or I make it. What's your excuse?”

Bruce faltered, suddenly having the urge to spill everything to his friend, his strange confidante, that he was slowly going crazy. Well, crazier. But how do you explain hallucinations to someone without sounding like you're at the end of your rope? He'd never seen the mysterious man's face, never seen much at all for longer than a few seconds, but it was also never the same actions. He'd move differently, or gasp for air, now always on his knees but still trying to shift position. It was like watching the film strip of a movie, frame by frame.

“I'm fine.” The lie was easy, and familiar. They all knew it, and that it rarely meant something so trivial as the few syllables it took to say it. Tony looked nonplussed.

“If you say so, Big Man, but you're looking a bit more green than usual and I don't think it's the Other Guy. You don't actually get sick, right?”

Bruce shook his head. “Not unless you count headaches.” Or delusions, it seemed.

“It counts. Take a few days off, for once. Even I get shoved bodily out of here by Pepper every so often to do adult-like things. You should try it.”

“What, adult-like things?”

“Hey, why not? I've got long and detailed lists of why adult activities are completely necessary to a healthy lifestyle. You're welcome to join me sometime.”

Bruce's face reddened. “Why do I have the feeling you're not talking about traveling and parties right now?”

Tony smirked, sucking his bottom lip into his teeth with a lascivious look that Bruce did not need to see, but would certainly remember.

“Offer stands. Seriously though, you're edgier than your usual squirrelishness, so if you need to talk, or even smash, just lemme know.” Tony slid himself gracefully from the desk and sauntered from the room without looking back. It was about as sentimental as he would get, really, and although it hadn't really shown, Bruce appreciated the concern. There weren’t many people Tony Stark considered worthy of being concerned over.

Two days later, and it happened again. But this time was much, much worse.

Bruce had hunkered himself down in the largest of the laboratories with the intent of using a few of the Stark patented machinery he'd never tried before. The battle with himself on finding a cure had hit a stalemate, even with the resources available to him, so there was little left to consider. If Tony's own machinery couldn't help, then perhaps the technology didn't really exist yet. Something Bruce had tried desperately not to realize.

It was after four in the morning, and the place was empty. The lights were focused only on the corner he'd situated himself in and the only sounds were the machines themselves. Previously, Tony had spent the entire night working with him, his own insomnia rearing its ugly head enough to give Bruce a lab partner. But the following night had Pepper dragging Tony off to who knows where. Probably to sleep. It was an interesting relationship, the two of them. Open, but possessive at the same time. Bruce tried not to imagine how that worked.

He was standing in front of a noisy centrifuge that currently held ten vials of his blood in different states of chemical induction. Bruce had done these tests before, but with varying results that might possible change if the correct equipment was at hand to study them. Seeing something at the molecular level and beyond was an opportunity to covet, so Bruce was doing exactly that with the hopes that he could get replicated results.

It was a far reach, but what else did he have to hope for?

Tony had been trying for weeks to get him involved on a few of his tech projects, and the idea of getting down and dirty with renewable energy innovation had been extremely tempting. But he couldn’t seem to let go of this one thing. Not yet. Not until all outlets had been exhausted. He knew Tony wouldn’t show his plans to just anyone, and Bruce hoped to utilize that invitation soon, but again, ‘soon’ was a time with no specifics.

The lights flickered, and Bruce cringed.

He switched off the centrifuge immediately, unwilling to risk the chance of something breaking once the power came back, then crouched to his knees. Despite how many times this had happened, Bruce was still determined to maintain himself as the smallest target he could manage, just in case.

The power went out completely, the flash of light flashed heavily from the corner of the room, and the powerful gust of air blew back Bruce’s hair as it expanded to every corner of the room before it was gone. Then silence.

Bruce held his breath, forcing calm into his heart even as his frustration grew more and more at being unable to explain what was going on. An incident with the Other Guy here would not be a pleasant, or a cheap one.

The lights came back on, and the mysterious man in the corner screamed.

Bruce was on his feet, eyes wide and heart stuttering in his chest even as he was already moving forward. Something was different this time. Something had changed, and there was no indication that the usual few seconds limit was in effect any longer.

The sound of agony was obvious, and Bruce could see the man on his knees clinging to his own arms with whitened knuckles as he rocked forward. Still naked, still alone.

Bruce approached slowly once he was within a few feet, waiting with baited breath for everything to just disappear again like he had before. But nothing was happening. The thin man was shivering, but he’d stopped yelling, his skin pale and littered with old scars and open, bleeding wounds.

“Hey…” Bruce spoke lamely, trying to keep his voice steady to keep from startling him. But he did startle, the man's head pulling back sharply to look at Bruce for the first time since everything had started three months ago. They met eyes and Bruce stared down at him in horror, all words sucked forcefully from his lungs.

It was _Tony_.

He looked terrible, wrung out and deathly pale with red rimmed eyes and a haunted expression. The scars on his body were everywhere; some years old and enormous like they’d been more than just a couple of quick stitches. His hair was graying, one ear was missing, and Bruce could see that there were only three fingers on his left hand. Also an old wound, long since healed.

Tony coughed and Bruce blinked, the horror and confusion seeping deep into him as concern shoved it’s way to the forefront of his mind. Whether it was actually Tony or not, this man needed help.

Bruce dropped to his knees, unsure where to put his hands but unable to tear his eyes away. What the hell was going on?

“Tony?” He asked cautiously, and the recognition in the other man’s eyes was suddenly there, his gaze taking in all of Bruce like he was the risen savior himself.

“B-Bruce. Bruce! Bruce Banner. _Doctor_ Banner. It…fuck, it is you. It _worked_. I knew it, I fucking knew it!” He made a sound that could have been a laugh if he wasn’t coughing up half a lung in the process, his arms still tightly wrapped across his bared chest.

“Tony, what? What the hell? What is this?!” Bruce felt his voice rise, but refused to consider himself in any danger just in case the Other Guy decided to view him as a threat. He started to move to find a first aid kit. “Let me get some-“ 

Bruce was halted in his tracks, Tony’s good hand clinging to his shirt like a vice.

“What day is it?” Tony asked, almost choking on his words, and it looked like an incredibly harsh battle to stay awake, let alone speak.

Bruce swallowed. “Wednesday.” He said numbly, unable to look away from those eyes. One was noticeably paler than the other, like it was partially blind.

“The date, Banner! February what?!”

“Twenty, uh…Twenty third. February twenty third.”

Tony nodded, relief washing over him visibly. “The year after the aliens, right? After the, uh…the Chitauri? When we all met?”

Bruce nodded slowly, his brain suddenly working double time as he took in all of the information available to him in an attempt to process. The healed scars, the age, the questions.

“When are you from?” He asked suddenly, and Tony barked out a humorless laugh, shuddering in its wake as a wave of shivers forced through him. Bruce stared at him in concern. “You need help, I can get a blanket at least. JARVIS? Can you-“

“That won’t work. JARVIS can’t hear you; no one can. You’re outside of time right now, Banner. Sorry about that.” Tony said it so simply, such impossible things.

Bruce stared, unable to figure out what to ask or say next.

“It’s okay. This is- this is what we planned. This is good. Ish. I’m sorry to scare you, I really am, but…” Tony trailed off, finally letting go of Bruce’s shirt to cling to his own skinny arms once again. “But I had to. I had to. You don’t know, you can’t. Not yet.”

Bruce’s curiosity was winning out over his anxiety. He leaned forward, eager for information and answers that months of his own contemplation had not given him.

“When are you from?” He asked again, and Tony smirked in that familiar way that made it obvious it couldn’t be anyone else.

“Ten years from now, everything is shit. It’s hell, everywhere. We couldn’t stop it, we couldn’t contain it, fuck, we couldn’t even _fight_ it. FUBAR doesn’t even begin to describe the world I live in, Banner. You just- you don’t even know.” Tony’s face was haunted and drawn, a story written into the deep lines of age around his eyes and the badly healed wounds across his body.

“How? What happened?” Bruce asked finally, wishing he could do something, anything to help Tony as he knelt naked and exposed on the floor. He couldn’t even begin to process the information of ‘time travel’ and ‘from the future’ without feeling like his head might explode.

Tony cried out suddenly, and it jarred Bruce’s senses, the man’s fingers clenching into his biceps as he shook with a pain that Bruce couldn’t see the source of. He reached forward, hands supporting on Tony’s arms and helping him to lean back slightly to keep from falling to the floor. Tony was like a puppet, limp and weak and more human than he’d ever seen the man.

And then Bruce saw it.

In the center of Tony’s chest. The place where he’d long gotten used to the sight of the soft blue glow that was keeping the shrapnel in the man’s heart from killing him, was an enormous, gaping, metal hole.

Bruce had seen the metal casing before, when Tony had needed his assistance in fixing a few fried wires deep within the bowels of his chest. Without the arc reactor, it was nothing more than a large cup, wired inside him to the nines with electrical genius that had once been the size of an entire building, yet somehow fit snugly where it lay. Tony’s crowning achievement. His heart and his brain merged into a single object.

And it was gone.

“Tony. Your _reactor_. Where’s your- what’s going on? Are you-“ Bruce couldn’t figure out what to do first, his fingers twitching at the dangerous lack of repulsive technology. Tony wearily shook his head.

“It’s okay. Big Guy, it’s alright. I already know. Fuck, it’s so good to see you. If it could have been anyone I chose- anyone at all for this to attach itself to, I’m really fucking glad it was you.” Tony’s good hand moved to Bruce’s and his fingers wrapped gently over his with a tenderness that took the man by surprise.

“Attach itself to? Is that why I kept seeing you everywhere for three months? How many times have you tried this?”

Tony sighed, somehow looking even more exhausted than before. Bruce couldn’t stand the shivering any longer as he quickly unbuttoned his own over shirt to wrap it around Tony’s bony shoulders. He still wouldn’t let Bruce move away from him, but he could allow this much at least, leaving him in his white undershirt.

“One try. One way trip only, but it’s not an exact science. Not even a pleasant one. Think of it like…like throwing a rock across the surface of a lake. Your target starts out as the lake as a whole, but eventually, even if you touch certain areas on the way in, you’re gonna reach a point where gravity kicks back in and it just…comes to a stop.” Tony explained carefully, and Bruce was surprised that he understood exactly what he was saying.

He’d been seeing Tony over the past three months like it was a skipped tape, but for Tony himself, it had all been instantaneous. He’d just had to wait until time pushed play.

“Wait…one way trip?”

Tony groaned, his skin somehow even paler as Bruce reached for him again, supporting him as he reached for the man’s wrist in concern. He swallowed, feeling the stuttering heartbeat and knowing what it was.

“You’re dying.” He stated, and it didn’t seem to come as any surprise to Tony.

“Wouldn’t be the first time. Had to be me though, always had to be me. Sucks, right? But seriously, thank fuck it’s you too cause this just might work. I haven’t got a lot of time left and I need you to listen to me, okay?”

Bruce nodded, staring at him seriously. “You knew this was going to kill you, but you did it anyway. Why?”

Tony swallowed hard, his eyes shifting with a sudden nervousness that resembled desperation. The look of someone who’d seen hell.

“Because it needed to be fixed. All of it. We can’t stop it, we can’t even begin to fight it, but…but I could do this one thing. It took us years to figure it out, too. That exact moment, something inconsequential and harmless that would trigger the hurricane halfway across the planet and set everything in motion.”

“You’re talking about the Butterfly Effect.”

“Exactly. Geezus I cannot tell you enough how glad I am to see you, Banner. If it had been Steve or hell, _Thor_ …we’d still be fucked.” Tony’s eyes rolled back slightly, his breath catching with a stuttered hiss in his throat. Bruce shifted his weight, taking more of Tony’s as the man seemed to deflate more and more as time went on.

“I can get you one of the arc reactors from this time, Tony. Let me help you, please.”

Tony shook his head, a hand moving to the gaping hole and covering it. “No. No dice. I couldn’t come through with it and I can’t go back with it either. No matter how antiquated it is. I'm not still using palladium in this time, right? The risk of it detonating was just too high on the way through. If somehow- if this doesn’t work. If you can’t…then I don’t want to go back as a bomb filled carcass to just make it all worse. It’s alright.”

Bruce felt his heart clench painfully, clinging to the scarred body of his friend, even if he was from the future, and knowing that he was going to die. Knowing it and being unable to do a damn thing to stop it.

“What must I do?” He asked, choking down the bitterness to deal with later. Much later.

“Don’t let me get on that plane.” Tony stared at him unblinkingly, a manic look passing over his expression. “The me that’s here, in this time. Tomorrow. Pretty sure it’s tomorrow, all of this time crap makes it hard to keep everything straight. Moscow. Don’t let me go there, just- do whatever you can, okay? Tie me up. Hold me down and sit on me. Start a fire or turn into the Hulk and smash the plane, I don’t fucking care. Just don’t.let.me.go. Do you understand? Can you do that?” Tony looked so sincere, so _scared_ as his fingers dug into Bruce’s arm desperately.

Bruce nodded quickly, and whatever adrenaline Tony had left was suddenly draining from him quickly. He cringed, trying to fold in on himself as the shrapnel inside killed him slowly, but not really having the strength.

“If this works,” Bruce said softly, cradling Tony as gently as he could. “You won’t exist anymore, will you? That entire future, won’t it disappear?” He’d never been an expert on quantum mechanics, but the basics were simple enough. How the paradox worked at that point, however, he wasn’t really sure. If this Tony disappeared from existence, then there was no way for him to travel back and warn Bruce, therefore no way for this entire conversation to happen in the first place. Which could also mean that he fails, but Bruce didn’t want to think like that. He lived with superheroes now, and paradoxes seemed to happen all the time.

“I won’t exist. And neither will they. Good. It won’t happen. It won’t. It just won’t.” Tony had tears falling from his red rimmed eyes, and Bruce couldn’t help but reach a gentle hand to wipe them away. He wanted desperately to ask more, to find out who ‘they’ were and what had happened and how Tony had gotten himself to this desperation so willingly.

“I should never have let you leave.”

It was spoken so softly that Bruce almost missed it. Tony moved to touch Bruce’s hand on his face, the three fingers that were left were shaking terribly in his obvious pain.

“What?” Bruce asked gently.

Tony swallowed. “If I could do it again, if it was me I was laying here talking to, I’d tell him not to let you leave. Of all the things I could yell at him about, and there would be a long ass list, it would have to be that. If I’d known what- I’m so- so _sorry_. Bruce. I should have protected you. I never meant for-“ Tony choked on his words as Bruce stared at him with terrified eyes. The final confession of a man who knew he was going to die and could voice nothing but his own regrets.

“Time’s almost up.” Tony said after a moment, smiling despite himself. Bruce shook his head, unable to accept it, even if it wasn’t the Tony of his time that he was holding. It was still Tony.

“No.” His fingers tightened, wrapping around the shuddering form in earnest. A small laugh and a gasp of air came out in reply, and after a second, Tony finally sighed beneath him.

“JARVIS won’t have seen me. This is all happening…in less than a h-heartbeat. You’ll have no p-proof, Bruce. I’m s-sorry. But please. _Please_.” Tony Stark didn’t beg, or apologize. He didn’t cry, or refuse to fight, or give up his life so easily unless it meant something. Something important.

Bruce nodded his head in silent promise, tucking it against Tony’s chest as he found himself suddenly unable to cope with looking at the man’s face any longer. He clenched his eyes shut, knowing that gaping hole was right in front of him but not caring. Not wanting to see any of it.

In Bruce’s arms, the Tony from the future died.

Bruce didn’t move, his heart racing as there was a thundering howl of despair from within him. The Other Guy was furious in his distress, shaking the bars of his cage but unwilling to reveal himself even if Bruce had wanted to. The air was too thick with sorrow, and without any time at all to come to terms with it, the lights started to flicker around them.

Bruce cried out angrily, screaming his sadness into the frozen air before it was suddenly all moving again. Time was shifting, running in place as it usually did in a normal, functioning dimension and leaving him clinging to nothing. His own, empty shirt slipping down between his elbows, and Bruce let himself slide to the cool floor as he buried his face in it.

It was too much. All of it. He couldn’t handle this, let alone begin to process everything he’d just seen and heard from a time that was not his own.

_‘Dr. Banner?’_

Bruce startled, gasping in a breath of air that sounded more like a whimper as he raised his head. He didn’t answer, but that didn’t stop JARVIS from continuing.

_‘Are you in need of assistance, Doctor?’_

It was laughable, really, and Bruce almost did just that, but if he had there would be no way to stop. He couldn’t form the words. Couldn’t pull together his thoughts enough to relay what had just happened when there was every indication that to the rest of the universe, it hadn’t.

_‘Do you require the use of the panic room?’_

JARVIS’s insistence must have meant that Bruce looked a wreck. Probably read it as a possible Hulk out where he could show him the quickest route there and then alert the rest of the tower. Bruce considered the question for a moment before leaning back on his heels and slowly shaking his head. He wasn't transforming. There was no danger.

There was blood on his shirt.

Bruce walked to bed on autopilot. Once in the dark room, he used the last of his brain power to remove his pants, but slipped beneath the covers in the undershirt and boxers he’d been wearing all day. Emotionally drained, despondent and terrified of what dreams would torment him in the non-waking hours of his life, Bruce fell unconscious quicker than he fell asleep.

Whatever time passed, Bruce was unaware of it. He didn’t dream, but then, the Other Guy might possibly have been as traumatized as he was. Whether it all had actually happened or was occurring only in his mind, the two of them experienced things on an emotional level that was often shared. 

If Bruce had feelings for Tony, so then would Hulk, even if it wasn't the same feeling. If his eyes and his arms captured the memory of one of the only friends he had _dying_ , then it was a sorrow the both of them would always know. He’d been spared of dreams that night, probably due to shock, but Bruce knew he wasn’t going to stay that lucky.

Before he could contemplate all of this, however, it was the silhouetted figure sitting next to him on the bed that had really pulled him from his slumber.

Bruce startled, his breath already stuttering in his throat as he shoved back, his entire body prickling and on edge. The figure didn’t move back, but as Bruce’s eyes adjusted, there was a familiar soft, blue glow that was giving the identity away before any words were spoken.

“Hey, whoa Big Guy, it’s just me. Didn’t mean to stop your heart or anything.”

Bruce couldn’t help it, he let out a choked sob at those words as he lost it completely.

Nothing else was spoken, but Tony was suddenly just there. Holding and encasing and supporting just as Bruce had done for him. But not him. Future him. _Dying_ him. The thought wasn’t comforting at all. Stress and shock poured from him like a poison, inhibiting him completely before he was finally able to pull himself back together. Eyes stinging and nose clotted with the embarrassing aftermath of crying your stupid heart out.

“JARVIS, ten percent lights please.” Tony said softly, and the computer complied, filling the room with a soft yellow glow.

Bruce scrubbed his hands over his face, suddenly nervous about the emotional exposure he’d subjected his friend to and wishing he could somehow purge it from his memory. Had it all been a dream? Was he asleep this entire time and conjuring terrifying futures of his dying friends? It certainly wouldn’t be the first time, but he had to admit, it was the most creative and horrifying experience he’d come up with yet.

And then Bruce took a look around, and realized where he wasn’t.

“I…where am I?” He asked groggily, Tony’s arm still wrapped around his shoulder even if the man himself was not.

“My room.” Tony shrugged, and Bruce glanced at him in dawning dread. “I kinda figured with the way you stumbled in here at four AM that you were either drunk or, well, not firing on all cylinders. So, bad dream huh?”

Bruce just stared at him, his face so close as he looked at him with a guarded kind of concern. Bruce’s eyes flickered to the reactor beneath Tony’s shirt, unable to stop his shaking hand from reaching for it and gently tracing his fingers around the edge to remind himself that it was still there. Tony glanced down at his own chest, then back to Bruce with a calculating expression.

“Ouch, bad dream about me? I’d say I’m flattered, but I prefer to be in people’s more adult rated dreams, thanks. What happened?”

Bruce shook his head, still staring at the glowing light with heavy lidded eyes. “I’m- I don’t…the line between dreaming and awake is so obscure right now. I can’t separate, or…” He trailed off, unsure what he was really saying or why. Tony didn’t pry, but he didn’t look satisfied with the answer, a rare, serious look passing over his usually apathetic expression.

“Wow, that’s really got you shaken up.” There was a soft beeping sound from the lamp side table and Bruce heard Tony make a small cursing noise under his breath. “Listen, I’m not trying to duck out or anything, I swear, but that phone is only going to get more annoying as time goes on. Pepper’s got me on company duty today and weaseling out is gonna be threat to life and limb. You’ll pardon me if I choose life?”

Bruce cringed at the wording, but he didn’t move as Tony slid himself carefully from the bed, releasing Bruce in the process. The heat was missed almost immediately and Bruce shivered.

“Before your brain starts processing correctly and you freak out for stupid reasons, just know that I don’t mind you being in here, okay? It was a bit of a surprise, but not an unwelcome one, and I’m glad that- well, I’m glad that you didn’t have to wake up alone after...that. Take of it what you will.” Tony stepped into the bathroom and shut the door, the sound of a running shower drifting into the quiet room as Bruce sat in silence.

He didn’t want to move. Bruce’s entire body felt as strung out as it was when he came back from a transformation, which made no sense whatsoever since he hadn’t really changed or gone anywhere.

But hadn't he? What had the man called it? _(Not any man, Tony)_. Existing outside of time _(Ten years in the future, everything has gone to hell)_. Unable to keep the arc reactor with him for the fear of carrying a bomb in his chest. _(One way trip)_.

Bruce scrubbed his hands through his mess of curls and tried desperately to sort his thoughts. It was already slipping through his fingers like water, _(skipping a stone across a lake)_ and draining back into the recesses like a dream would. There had been something important about it, however, something that he had been meant to remember. To act upon.

He didn’t realize how much time had passed before the door to the bathroom was opening and Tony had sauntered back out in a towel. He paused when he saw Bruce, still in the same position he’d left him in, and the lines between his eyes creased in worry _(lines of age, pinched at the edges of his eyes and graying his hair from a decade of horrors)_.

“Geezus, Banner. That really did a number on you.” He pursed his lips before turning to walk towards his closet. “Hell, if it wasn’t for this stupid thing in Russia, I swear I’d stay with you. Your timing to have a traumatic experience is terrible, not that I think you did it on purpose, but-“

“Moscow.” Bruce’s voice was unsteady, but loud enough to hear.

Tony took a few steps backwards so he was in the room again, an eyebrow raised in interest. “Well, yeah actually. Did Pepper tell you-“

“No.”

Tony paused for a beat and blinked. “No…what? She didn’t tell you? Or-“

“Don’t go.”

Tony looked taken aback at the suddenly serious look on Bruce’s face. His eyes clear and slightly glowing with a greenish hue. He took a few steps toward the bed, water from the shower still dripping down his bared chest where the reactor glowed a bit more brightly without fabric to cover it.

“Banner, what’re you-“

“You can’t go, Tony. You just can’t. Please.”

“Is this about your dream?”

“I- I think so, yes.”

“You think so? So, what, was it a bad omen? Did I die in a plane crash? Did the Russians try to kill me? How did you know it was in Moscow any-“

“ _Please._ ”

Tony’s teeth clacked together, whatever else he was going to say dying in his throat as they stared at each other in awkward silence. The phone on the lamp table beeped again and it broke the moment as Tony cursed and headed back into his closet. Bruce stood from the bed as Tony's voice drifted from within.

“Look, I will be the first to agree with you that nightmares are, well, the stuff of nightmares. But you don’t understand what Pepper will do to me if I skip this one. It’s nothing against you, Big Guy, honestly, and I appreciate you looking out for me when you get a bad feeling, but that ain’t gonna fly if I don’t fly. I don’t like it any more than you do, but I’ve done it enough times to-“

Tony froze after zipping the fly on his suit pants, reaching for a button down shirt just as he noticed that Bruce was standing in the doorway to the room sized closet. Blocking it.

“Bruce.” He said, almost as a warning before his shoulders loosened and he sighed, running a hand back through his damp hair.

“You can’t go.” Bruce didn’t know how else to put it. He wasn’t even sure where it was coming from except that this was the one thing he had to do. _(Tie me up. Hold me down and sit on me.)_

“Can you at least tell me why?” Tony didn’t sound angry, but he was definitely frustrated. 

“It’s not just a feeling. Not just a dream. It can’t be.” _(Just don’t.let.me.go.)_ Bruce swallowed, suddenly feeling nauseated. “He told me Moscow. He said it to my face. With that hole in his chest and years already off his life.”

“Okay, now you’re seriously starting to freak me out. Bruce? You weren’t drinking, right?” For Tony to be asking him that was an interesting irony, and it made Bruce bark out a huff of laughter that bordered on maniacal.

“He gave his life to tell me.” The edges of Bruce’s eyes pinched and he tried hard not to blink them. Tony took a few steps toward him, but Bruce didn’t move.

“Who did?” He asked, but didn’t look like he wanted to know.

“You.” Bruce breathed, a hand moving to touch the reactor again. To know that it was there. “You did and then you died.”

“In the dream?”

“Not a dream. You gave your life to change it, so it _has_ to change.” Bruce felt himself splintering. “The future can’t happen like that, and I’m so sorry. The reactor was just gone and I couldn’t help you, I tried, but you wouldn't let me, I’m so…” He shook his head, and Tony seemed to debate with himself internally before he was suddenly just there. Lips and arms and heat and hands touching Bruce everywhere as he was pulled into the closet and pushed bodily against a wall.

Bruce clung to Tony desperately, everything boiling over into this fixed point that he never thought would happen. To touch and to taste and feel the sensations of being needed and wanted without words. He was sliding his tongue across Tony’s lips before he even had a second to think about it, the man’s fingers _(ten of them. Nothing missing)_ dragging underneath the edges of his undershirt in the search for more skin.

The few tears on his cheeks were kissed away as Tony broke from his lips and dragged his lips across stubbled skin to the tenderness of his neck. Bruce groaned, bucking forward as Tony pressed his hips into him, making it clear that there was only one direction he intended on taking them.

“I believe you.” His voice rumbled and Bruce's eyes slid closed.

“Don’t go” Bruce whispered, his hands wrapping around Tony’s ribs and pulling them together seamlessly. “Don’t go. Please.”

“I’m not. I’m not going.” Tony’s voice was only air, and Bruce felt it on his skin like ice on fire. He felt hands move to his ass and grip there tightly as he shifted his weight upwards and wrapped skinny legs around Tony’s waist. Tony took a step away from the wall, Bruce’s face buried in the crook of his neck and his arms crossed over the man’s shoulder blades. It wasn’t until everything suddenly went horizontal that Bruce realized Tony was leaning him backwards onto the bed.

For a second, Bruce panicked, thinking that Tony was placing him there just to get around him. Get past him and out the door. But their only separation consisted of Tony reaching over to turn off his cellphone before tossing it wordlessly to the floor.

“I never liked Moscow anyway.” He mumbled before straddling Bruce’s hips and going back to what they’d started. Bruce had no more argument to make otherwise, as long as he didn't go out that door.

Hours later, whatever time, or day, or year it was, Bruce didn’t care.

They were so close beside each other that there was no space between them. Bruce's fingers gently touching the arc reactor with his head tucked beneath Tony's chin. It had been quiet, after wards, but not the awkward kind. Bruce could tell that Tony was still worried about him, but after everything finally came back to him in a logical time frame, Bruce had willingly spilled it all.

“Did he say what they were fighting? Or at least, trying to fight?” Tony asked, his fingers curling over Bruce's bared thigh beneath the duvet.

“No. He just called it 'them'. He had so many scars, some that were years old and criss-crossed over other ones. It didn't look like they'd even been sewed up correctly. War medicine; messy sutures on the fly when things just didn't have an end.” Bruce shuddered, trying not to imagine that the place that future Tony had come from even existed anymore.

Tony was silent for a minute as they both breathed, the small amount of morning light bleeding in from the closed windows arching shadows across his face.

“What was in Moscow?”

Bruce shook his head. “No idea. But that was the catalyst. The inconsequential thing. He said it had taken them years to figure it out, but he didn't mention any other events. Nothing else to look out for. Just that.”

“How annoyingly vague. That's not like me at all.”

Bruce laughed soundlessly, despite himself. The images were still there, the memory was still fresh, but he had Tony in his arms _(not dead)_ , had stopped him from leaving _(at any cost)_ , and had somehow ended up having sex with the man in the process. The first time he'd allowed himself something so intimate in nearly a decade. He couldn't altogether say the methods were regrettable.

“Do you think it's changed?” Bruce asked, unable to help himself. It wasn't a question they could logically answer.

Tony shrugged. “No way to know, really. Unless a me from some _other_ dimension decides he doesn't like his life either. I hope this doesn't become a thing, I'm terrible with that kind of competition. Hell, the time paradoxes alone are giving me a migraine.”

Bruce snorted. “I went through that already. The existing to promote non-existence whereby you would then never exist in the first place in order to reach the point of existence to warn of non-existence. Yeah. Been there.”

“Your brain has gotta be the sexiest thing I have ever not-seen. As awful as the whole- time stopping, me from the future dying miserably thing went...I'm kinda glad it at least got you to stumble into my room in barely conscious, traumatized shock. Well, minus the traumatized thing, that had to suck.” He sniffed knowledgeably. Bruce rolled his eyes.

“Is that why you believed me? I probably looked like a serial killer blocking the doorway like that.” Bruce grimaced, trying not to relive the adrenaline fueled mania. “I thought I was losing my mind.”

“Well, yeah. No. That isn't directly why I believed you, but it certainly helped. The skinny door block notwithstanding.” Tony chuckled, but Bruce knew it was an empty jab. His human form wasn't all that imposing, but beneath it lay something far more dangerous that could easily have been provoked from Bruce's previous state.

“To be honest, after I watched you stumble in here and conk out, JARVIS insisted on filling me in about this really weird thing that happened in one of my labs tonight.”

Bruce could almost hear his own heartbeat, his fingers freezing on Tony's chest as he swallowed hard. “Oh?”

“Indeed. It seems as if there is recorded footage where you go from one side of the room, fully dressed and sitting at a desk...to the complete opposite side without your a shirt and on the floor. All in the span of a quarter of a seconds time.”

Bruce pushed himself up on one elbow as Tony rolled onto his back. He stared down at him searchingly, going through his memories of each time the event had taken place.

“I had never really moved before except to crouch by my desk. Each time was never long enough, a few seconds at most, before he was gone. So I never moved towards him. Until that last one.”

Tony nodded. “It's not concrete evidence, but unless you've suddenly been reborn as the Flash, maybe then something was messing with the camera or clock. Unlikely. So as the me from the future said, you must have been outside of time. And I'm willing to bet that the shirt you zombied in here with on the floor over there has blood on it that would test positive to mine.”

Bruce's eyes glanced to the rumpled lump of fabric on the floor, the thought somehow not occurring to him that the blood belonged to someone that no longer existed, but was still right in front of him.

“This entire thing is weird beyond my pay grade.” He mumbled, and Tony smiled.

“At least you didn't have to do anything more than stop me from going to Russia. It could have been some bizarre, Terminator shit where you had to actually kill me. Which, by the way, good call on the method of stalling. Pepper is gonna hang me from the balcony when she gets back, just so you know. This entire endeavor could have been for naught just because of that, cause now I’m getting murdered by an angry redhead in high heels instead. Boizhe moi.”

Bruce grinned. “From what I recall, all I did was beg you to stay, you kissed me first.”

“You didn't argue.”

“Well yeah, the plan was working.”

“What plan!? I had to do all the work!”

“I'll consider it an assist. Besides, at the time, you thought I was crazy.”

“And that much hasn't changed, but more importantly- in fact, _the most_ important thing that we haven't really addressed about this entire fiasco...something that could, quite possibly, change the fate of every living thing on the surface of this planet...”

Bruce blinked down at him wordlessly, waiting for the other shoe to drop.

“Is that in the future, I invent time travel. I'm a fucking _mastermind_.” Tony finished gleefully, a look of evil genius bleeding across his face.

Bruce groaned and buried his face in a pillow.

~*fin*~


End file.
